In antenna engineering, high demands are placed on the contact between high-frequency elements. One primary problem with contacting is posed by undefined contacts between high-frequency conductors due to the unfavorable design of the contact points. In high-frequency engineering, these undefined contacts lead to undesired passive intermodulation products, abbreviated as PIM, which result from so-called intermodulation. Intermodulation is the parasitic mixing of two different carrier frequencies, which leads to so-called harmonic waves, which are precisely the passive intermodulation products that can result in interference. An unfavorable contact point results, for example, from increased wear at the contact points. Tolerances such as roughness and (un)evenness, as well as clearances in many cases, that result in undefined contacts are a primary reason for undesired intermodulation.
Galvanic contacts between high-frequency components, for example, are contacts between dipole and reflector or other components and reflector, a lid on a housing, or even contacts of high-frequency switches.
Secure galvanic contacts are usually produced by pressing and/or screwing conductive surfaces of two conductors together. Due to the fact that the contact must be permanent and secure, a high force effect is required in order to achieve this. This results in high production cost. What is more, it is problematic that small gaps or recesses can form between the conductors if the surfaces are not completely flat or if one of the surfaces is mounted slightly askew, whereby the electric current and hence the characteristics of the contact can remain undefined, and undesired intermodulation can occur. These tolerances can be compensated for in part by extremely high force during pressing, but that, in turn, results in high production cost and a great amount of energy, and high structural demands are placed on the geometry.
For movable contacts such as high-frequency switches, galvanic contacts are produced by contacting a fixed element by means of two movable conductors, for example. The shape of the fixed element determines the mating shape of the other conductor. Standard contacts are produced by means of level surfaces, as shown in U.S. Pat. No. 6,043,440. Alternatively, a fixed element is shown in U.S. Pat. No. 2,662,142 that has beveled shapes at the points of contact with the conductors. The conductors for switching also have beveled surfaces in order to enable a maximally planar contact to be produced. Another alternative is shown in U.S. Pat. No. 3,226,515. Here, the contact is achieved between the conductors for switching by means of a spherical switch element that can be slid by means of a switch grip mounted on it that establishes the contact between two conductors. This is made possible by disposing a spring element in the switch grip by means of which the switch element can be pressed over the middle conductor, which enables the switch element to establish an electrical contact between the middle and an outer conductor. Advantageously, a spherical switch element and spherical conductors are used here for the contacting, since less force needs to be applied in order to slide the switch element over the middle conductor.
In the known switches, no consideration is given to an intermodulation-free connection or to greater tolerances or unevenness; their aim is merely to achieve sufficient contacting of the conductors.
For the above reasons, it is an object of the present invention to provide an arrangement in which a reproducible, permanently good intermodulation-free electrical contact can be established between high-frequency components and associated contact elements. This object is achieved according to the invention through the features of patent claim 1. Advantageous embodiments are also the subject of the dependent claims.